Cargo release for parachutes



y 1968 w. L. BECKWITH, JR 3,393,001

CARGO RELEASE FOR PARACHUTES Filed Jan. 23, 1967 4 Sheets-Sheet l INVENTOR.

BY .7. J w,.w 5 W 8% LuaZier L.BeckwHh Jr:

y 6 w. L. BECKWITH, JR 3,393,001

CARGO RELEASE FOR PARACHUTES Filed Jan. 23, 1967 v 4 Sheets-Sheet 2 g gs.

INVENTOR. wall'er L. fieckwl'f J1:

Jamal/- M 6 July 16, 1968 I w. L. BECKWITH, JR 3,393,001

CARGO RELEASE FOR PARACHUTES Filed Jan. 23, 1967 I 4 Sheets-Sheet 5 INVENTOR. Qblfer L Bea/WW7, Jr: -fi y 7n. J I my. Z 5

y 6, 1968 w. L. BECKWITH, JR 3,393,001

CARGO RELEASE FOR PARACHUTES Filed Jan. 23, 1967 4 Sheets-Sheet 4 IN V EN TOR.

United States Patent 3,393,001 CARGO RELEASE FOR PARACHUTES Walter L. Beckwith, Jr., Warwick, R.I., assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Army Filed Jan. 23, 1967, Ser. No. 611,177 15 Claims. (Cl. 294-83) A cargo parachute release device used to attach parachutes to a cargo for aerial delivery. The release device being of the tilt type actuated by inequality in load suspension tensions caused at landing when the parachutes blow to one side.

In the dropping of loads by parachute it is important that the load be disconnected from the parachute immediately upon contact with the ground, so that the load will not be dragged by the parachute. Heretofore most releases were of the relaxation type which depended upon reduction of the suspension tension or weight of the load upon the parachute for operation of the releasing mechanism. Such releases have failed to operate reliably in high winds however, due to the action of the wind which caused dragging of the load by the parachute with little or no reduction in suspension tension.

An important object of the present invention is to provide a disconnect or release mechanism of the tilt type which is actuated by inequality in load suspension tensions caused at landing when the parachute blows to one side. Such a release mechanism operates best in high winds where relaxation type releases would frequently be inoperative.

Another object of the invention is the provision of an arming device of the time-delay type which will prevent premature operation of the release mechanism or disconnect during deployment of the parachute when there may be periods of no load tension on the parachute suspension members.

A further object of the invention is to provide a cargo release mechanism which may be re-used as frequently as desired, which is certain in operation, and which is capable of withstanding rough usage without impairment of its operation.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings which form a part of this specification and wherein like characters of reference denote like parts throughout,

FIGURE 1 is a perspective view of a disconnect or release mechanism illustrating its connection to the finger type parachute suspension lines and to the cargo suspension slings and cargo,

FIGURE 2 is an elevation of the release mechanism,

FIGURE 3 is a vertical sectional view on line 3-3 of FIGURE 2,

FIGURE 4 is an edge elevation of the release,

FIGURE 5 is an elevation of the release with one of its side plates removed,

FIGURE 6 is a schematic view similar to FIGURE 5 and illustrating the locked position of the parts of the release during the deployment stage of the parachute drop,

FIGURE 7 is a similar view showing the unlocked or armed position of the release parts,

FIGURE 8 is a similar view illustrating substantially the maximum safe tilt position of the release in which the suspension fingers are locked to the release,

FIGURE 9 is a similar view illustrating the parts tilted to the release position,

FIGURE 10 is a horizontal sectional view through the cylinders of the hydraulic form of time delay device,

FIGURE 11 is a fragmentary sectional schematic view taken on the line 11-11 of FIGURE 4 and illustrating the locked position of the parts,

FIGURE 12 is a similar view of the release with its parts in release position,

FIGURE 13 is a fragmentary vertical sectional view of the hydraulic time delay mechanism, taken on the line 1313 of FIGURE 10,

FIGURE 14 is a fragmentary elevation of a release which employs a pyrotechnic type time delay mechanism,

FIGURE 15 is an edge elevation of the portion of the release shown in FIGURE 14 with parts broken away,

FIGURE 16 is a fragmentary view similar to FIGURE 14 with one of the side plates removed to show the locking mechanism employed with the pyrotechnic type time delay, as indicated in line 1616 of FIGURE 15,

FIGURE 17 is a perspective view of the lock release element shown in FIGURE 16,

FIGURE 18 is a fragmentary schematic view similar to FIGURE 16 but showing the unlocked position of the lock release,

FIGURE 19 is an exploded perspective view illustrating the principal parts of the release mechanism, the lock mechanism being shown in reverse position for purposes of illustration, and,

FIGURE 20 is a perspective view of the lock mechanism shown in FIGURES l6 and 18.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of the invention, the numeral 20 designates the release mechanism or disconnect broadly which is connected to the cargo or load platform 21 by means of suitable slings 22. The slings 22 engage the platform 21 adjacent its four corners and pass through clevises 23 pivoted to the lower portion of the release mechanism. Where the cargo platform 21 is longer than it is wide, it is desirable to arrange the slings so that the long dimension of the release mechanism is normal to the long dimension of the cargo platform. While the length of the slings is not critical, it is desirable that they be of such lengths that the dimension A in FIGURE 1 is approximately one and one-half times dimension B. Qne or more parachutes may be attached to the upper portion of the release mechanism by the usual suspension slings of the pivoted-finger type illustrated generally at 24 in FIGURE 1 and in more detail in FIGURES 2 and 3.

The construction of the release mechanism is most clearly illustrated in FIGURES 2, 3, 4, 5 and 19 while the operation of the release is best illustrated in FIGURES 6, 7, 8, 9, 11 and 12. Referring to FIGURES 2, 3, 4, 5 and 19 it -will be seen that the main body of the disconnect or release mechanism comprises two side plates 25 and 26 which are very similar but not identical and which are bolted together to form the main body of the release mechanism. The lower end of each side plate is provided at each corner with an inwardly otfset and laterally extending car 27 having an opening adapted to register with a similar opening 28 in the adjacent ear of the other side plate so that the bolt 29 of the sling clevis 23 may be passed through the ears. Smaller openings 30 in the ears permit the plates to be bolted together with the openings 28 in registration before the clevises 23 are pivotally attached by the bolts 29.

The inward offset of the cars 27 serves to separate the plates 25 and 26 to provide a space between the plates for the reception of other elements of the release mechanism. The spacing of the plates at their upper ends is maintained by an abutment or bridge 31 provided with aligned and reduced threaded studs at each of its ends which pass through openings 32 near the top of each plate and are engaged exteriorly of the plates by suitable locking nuts 33. The main or upper portion of each of the two plates 25 and 26 is of generally circular configuration merging at its lower end into a wide base which terminates at each side in the cars 27, as best illustrated in FIGURES 2 and 19. The inner surface of each of the plates is provided with an arcuate groove 34 concentric with and in closely spaced relation to the upper periphery of the plate. The grooves 34 extend through an arc of about 230, and slidably receive the side edges of the base of an arcuate clamping slide 35 which has spaced upstanding flanges 36 to form a channel for the reception of the ends of the sling fingers 24. The slide 35 is considerably shorter than the grooves 34 and is freely movable in said grooves.

The inner surface of each plate 25 and 26 is also provided adjacent its upper end immediately adjacent the inner periphery of the arcuate slot 34 with a thickened portion 37 provided with a relieved area or socket 38 surrounding stud-receiving opening 32 and closely surrounding the bridge 31. The walls of the socket 3-8 engage the bridge 31 so that load stress will be transmitted between the socket walls and bridge rather than through the bridge studs to openings 32 in the plate, thereby protecting the bridge studs. The lower surface of the bridge is provided with a pair of spaced semi-cylindrical grooved sockets 39 which extend longitudinally of the bridge and normal to the plane of each side plate. A toggle element 40 is provided on its upper surface with a pair of spaced semicylindrical ridges 41 which fit into the bridge sockets 39. The lower grooved surface of the bridge is complementary to the upper ridged surface of the toggle, as illustrated in FIGURES 6, 7 and 11, and due to the length of the mating surfaces there is a large area of contact between the bridge and the toggle.

Each end of the toggle is provided with a narrow vertically disposed raised rib 42 extending from the bottom of the toggle to a point adjacent its center, and a horizontal bore 43 extends through the central portion of the toggle and through the upper ends of the ribs 42 for the reception of a cylindrical toggle pin 44 which is sufliciently long to protrude a substantial distance beyond the ribs 42 at each end of the toggle. The protruding ends of the toggle pin 44 extend into guiding grooves 45 in the inner surface of the side plates. The grooves 45 are of scalloped shape and each consists of a pair of arcuate sections merging at the center of the plate, the arcs of which have a center which coincides with the center of the adjacent groove 39 in the underside of the bridge 31, as illustrated in FIGURES 11 and 12. With this arrangement of the grooves 45 and bridge 31, the toggle pin will rest at the juncture of the two arcuate slots 45 when the toggle is in its normally vertical position with its ridges 41 resting in the bridge sockets 39, as shown in FIGURE 11. If the lower end of the toggle is moved laterally, as to the right in FIGURE 12, the pin 44 will be guided by the right hand arcuate groove 45 and the toggle will fillcrum or pivot about the axis of the right hand bridge socket 39. If the toggle is moved in the other direction from its central position, it will maintain contact with the left-hand bridge socket 39 as it fulcrums about the axis of such left hand socket.

The main body of the toggle 40 is of substantially cylindrical form joined at its top to the spaced ridges 41, and a transverse slot 46 extends from the bottom of the toggle centrally thereof to a point above the central toggle bore 43 as shown in FIGURE 19. The toggle slot 46 receives an upstanding tab 47 carried on the lower downwardly curved arm of a four sided suspension link 48. The tab 47 is provided near its lower end with curved seats 47 to engage and support the lower curved surfaces of toggle 40 and near its upper end with an aperture 49 to receive the toggle pin 44 which maintains the tab within the slot 46 to pivotally secure the suspension link 48 to the toggle 40. The side arms of the suspension link 48 diverge upwardly and the upper arm of the link is curved upwardly, its lower surface having a very shallow V-shape as shown in 4 A FIGURE 3. The upper arm of the link 48 is relieved on both sides for the greater portion of its length and is normally spaced from the upper edges of the flanges 36 of the clamping slide 35 in substantially concentric relation thereto. In this operative locking position of the link 48 and slide 35 the pivoted sling-fingers 24 fit closely about the relieved upper arm of the link 48 with their tips or noses extending downwardly together between the flanges 36 of the clamping slide 35, as illustrated in FIGURE 3. In this normal locked position of the parts, the slide flanges 36 confine the fingers 24 against outiward pivoted movement away from the upper arm of the suspension link and maintains contact between the fingers and the side and flared bottom surfaces of the link arms.

The interior surfaces of the side plates 25 and 26 are provided with raised ribs 50 extending from the thickened portion 37 downward to the upper portions of the bases of the side plates. The lower portions of the ribs 50 are parallel but the portions of the ribs immediately below the thickened portion 37 are bulged away from each other to provide a generally bell-shaped chamber to surround the arcuate slots 45 and the toggle element 41 while permitting limited pivotal movement of the toggle 40 about the axis of either of the grooves 39 in the bottom of the bridge 31. The lower parallel portions of the ribs 50 form a vertically channel for the reception of a vertically movable locking mechanism which in the form of the invention illustrated in FIGURES 2 to 10 and 19 is of the hydraulic time delay type, although other suitable time delay mechanisms may be employed.

As illustrated in the lower portion of FIGURE 19, the lock mechanism comprises a rectangular base 51 provided on one side with a removable wall or cover 52 which may be secured in any suitable fashion to the base 51, as by small bolts (not shown). A pair of spaced upstanding lock bars 53 are carried by the base 51 and cover 52 and are normally disposed in the channel formed by the parallel portions of the plate ribs 50. The upper ends of the lock bars 53 are each bifurcated or centrally slotted as at 54 to slidably receive one of the toggle ribs 42 and thereby lock the toggle against lateral movement, as illustrated in FIGURES 5 and 6. The base 51 of the lock mechanism is arranged between the lower portions of the side plates 25 and 26 which are relieved at 55 to accommodate the base. The lock bars 53 are of such length that in the upper position of the base 51 the toggle ribs 42 are disposed within open slots 54 but in the lower position of the base the tops of the lock bars are completely below and out of engagement with the toggle and its ribs 42, as seen in FIGURE 7.

As shown in detail in FIGURES 10, 13 and 3, the base 51 of the lock mechanism is provided with spaced parallel horizontally disposed bores 55 and 56 which extend from side to side of the base and a substantial distance into the cover. The bore 55 serves as a cylinder to receive a driven piston 57 and its rod 58 while bore 56 serves as a cylinder to receive the drive piston 59 and its rod 60. Packing caps 61 surround each piston rod 58 and in the usual manner, and may be screw-threadedly or otherwise removably secured in enlarged end portions of the bores. The packing may comprise suitable felt washers carried by the caps and surrounding the piston rods. The drive piston cap is arranged substantially flush with the side surface 1 of the base 51 but the driven piston cap is spaced inwardly a substantial distance from the side surface of the base. A coil spring 62 surrounds the drive piston rod 60, exextending from the packing cap to the head of the piston, and the drive piston is relieved from its head to a point adjacent its middle. A cross hole 63 is bored from one end of the base 51 through cylinder 56 into cylinder 55 and is closed at the end of the base by a suitable plug 64. The driven piston 57 is of smaller diameter than its cylinder 55 so that air can pass from cylinder 57 through cross hole 63 into the other cylinder 56 when the relieved portion of the driven piston 59 uncovers a portion of the cross hole 63 and return, as the pistons are moved opposite directions. Each cylinder 55 and 56 is provided with an elastic flexible diaphragm 65 secured to the base in any suitable fashion, as by a beaded edge received in annular grooves in the base covered by the removable cover 52. The diaphragms extend from between the base 51 and cover 52, down the walls of the cylinders into the space between cylinders and pistons and up over the heads of the pistons, as illustrate-d in FIGURE 10. The cover 52 is provided with a duct 66 connecting the portions of cylinders 55 and 56 which extend into the cover 52, as shown in FIGURES and 13. The duct 66 may be formed by drilling the cover from end to end as shown, and then plugging the ends of the duct as by screw bolts 67 and 67'.

A vertical passageway 68 extends from the bottom of the cover 52 into and through the duct 66 between the ends of cylinders 55 and 56 and is provided with a screw threaded portion to threadedly receive a suitable screw time valve 69 which projects into the duct 66 to partially obstruct the flow of fluid through the duct. Suitable hydraulic fluid is passed into the diaphragm ends of the cylinders 55 and 56 by removing the screw 67 and inserting the fluid through duct 66. Screw 67 is removed for a suflicient length of time to permit air to be bled from the system while the fluid is being inserted in duct 66. After sufficient fluid has been inserted, screw 67 is then reinserted.

The driven piston rod 58 is of a length such that when the piston 57 is moved away from the cover 52 to engage the packing cap the end of the rod 58 will not project beyond the confines of the base 51. On the other hand, the drive piston rod 60 is considerably longer so that when the drive piston 59 is moved as far into the cylinder 56 as it can go, the end of rod 60 will project a short distance beyond the confines of the base 51. When the driven piston 57 is moved into its cylinder by applying pressure against the end of its rod 58, fluid is moved from cylinder 55 through duct 66 into cylnider 56 where it will act against the diaphragm to force drive piston 59 outwardly against the tension of coil spring 62. When the piston rods are released, tension of coil spring 62 will move the drive piston 59 back into its cylinder, thereby forcing fluid through duct 66 into cylinder 55 thereby moving driven piston 57 back to its starting position. The length of time required to return the pistons to their starting positions is controlled by the position of the time screw valve 69 which is adjusted to permit the desired rate of flow of fluid through the duct 66.

The plate 26 is shown in FIGURE 19 as provided with an opening 70 which will register with the open enlarged end of cylinder 55 in the upper position of the time mechanism so that access may be had to cylinder 55 and the end of piston rod 58 from outside of the plate 26. A vertical groove 71 is also provided on the inner surface of plate 26 to receive and confine the projecting end of drive piston 60 in its innermost position and to permit movement of the time lock mechanism from its uppermost operative locking position to its lowermost, inoperative release or armed position. The bottom of vertical groove 71 serves as a stop to engage the piston rod 61 and retain the lock mechanism between the plates 25 and 26 so that it will not be lost in operation. At the top of the vertical groove 71 and on a level with opening 70 is an opening 72 extending through plate 26 to permit passage of the end of piston rod 60 out through the plate. These parts are shown in FIGURE 19, but the position of the lock mechanism is reversed to illustrate the location of the piston rods which in use would extend in the opposite direction towards plate 26.

When setting the device for operation, the time screw valve 69 is set in the desired location, the lock mechanism is pushed to its upper operative position with the bifurcated ends of lock bars 53 receiving the raised toggle ribs 42 and with the openings 70 and 72 registering with the piston rods 58 and 60 respectively. In order to retain the lock mechanism in this uppermost and operative locking position, any suitable instrument such as a key or pencil is inserted through opening 70 and pressed against the end of rod 58 until the rod 60 is pushed out through opening 72 and projected outwardly beyond the plate 26 a distance suflicient to expose an opening 73 in the end of rod 60. The parts are then locked in this position by, inserting a safety or arming wire 74 downwardly through the opening 73, thereby preventing withdrawal of piston rod 60 from opening 72 under tension of coil spring 62. A cord or wire 75 connects the end of arming wire 74 to some part of the parachute such for example as one of the slings or lines in the usual manner to withdraw the arming wire when the parachute is deployed and thereby arm the release for operation when landing.

The hydraulic lock mechanism described is desirable because it remains connected to the release mechanism and can be reset in the field by moving to its upper looking position and setting the piston rod and arming wire as described above, without the replacement of any parts and without dismantling either the release mechanism or the time lock mechanism. If a change in the time delay is required, the screw valve 69 is accessible through the open space between the bottoms of plates 25 and 26. However, any other suitable time delay lock mechanism may be employed, and in FIGURES 14 through 18 a pyrotechnic time delay lock mechanism is illustrated as another possible arming device for the present release mechanism. In this type of arming device, the two vertical lock bars 53 are connected at their lower ends by a cross bar 51 as shown in FIGURE 2.0, but are otherwise of the same construction as the lock bars 53 of FIG- URE 19 with the exception of a slightly V-s'haped bottom surface illustrated in FIGURE 16. In this form of the invention, the latch comprises a sector shaped weighted body 76 eccentrically carried by a shaft 77 journaled adjacent the bottom edges of plates 25 and 26' transversely of said plates, the weighted body being disposed between the plates and spaced a sufficient distance from the plates to permit free movement of the latch body 76 around the axis of its shaft 77. The body 76 is provided on one side thereof adjacent its periphery with a finger 86 which is urged into engagement with notch 88 in plate 26 by means of spring 87 on shaft 77 between the opposite side of body '76 and plate 25 to prevent rotation of the latch until acted upon by the blast from pyrotechnic firing mechanism 83. A lever 78 extends away from the shaft 77 on the side of the shaft opposite to the weighted body 76 and terminates in a laterally projecting abutment 79 extending parallel to the shaft 77 and a substantial distance beyond the end of such shaft. The projecting abutment 79 extends through a notch 80 in the lower end of the plate 26 and outwardly beyond the outer surface of the plate. On the portion of abutment 79 which extends outwardly beyond the outer surface of plate 26' there is formed a projection 79' having an inclined surface 89 facing and in line with pyrotechnic mechanism 83. An upstanding detent 81 is carried by the lever 78 in a position in line with one of the lock bars 53 and in the operative locking position of the parts, engages the inclined bottom of the lock bar to support the lock bar in its raised position in locking engagement with the rib 42 of the toggle 40. This position is illustrated in FIG- URE 16 and also in FIGURE 5, as the locking position of the bars and toggle is the same with all forms of arming devices. In this position of the latch, as shown in FIGURE 16, the weighted body 76 urges the abutment 79 upwardly in the notch 80 to prevent disengagement of the parts due to accelerations during parachute deployment.

A casing 82 is secured to the outer surface of the plate 26 immediately above and in alignment with the notch 80, as by bolts or other securing means, and is bored vertically from top to bottom. A suitable pyrotechnic firing mechanism 83 is removably secured in the upper portion of the bored casing 82, as by screw-threads. The firing mechanism is well known, and may be of any suitable construction, such for example, as that made by Ordance Associates, part number OAA210. A reusable safety pin 84 prevents inadvertent firing of the pyrotechnic mechanism until it is manually removed. An arming wire or cord 85 connects the firing mechanism to some part of the parachute, such for example, as one of the slings or lines in the usual manner to pull on the firing mechanism during parachute deployment and thereby ignite the cartridge which after a predetermined delay such as ten seconds explodes a charge in the cartridge. The products of the explosion pass through the open lower end of the bored casing 82 and impinge on inclined surface 89 thereby imparting both axial and downward components of force thereon resulting in disengagement of finger 86 from notch 88 and the rotating of shaft 77 thereby forcibly moving detent 81 past the slight incline on the bottom of lock bar 53 and out from under the lock bar which then drops by gravity into the angle between the detent and the weighted body 76 to prevent rebound of the detent into locking position, as illustrated in FIGURE 18. With the parts in this position, the release mechanism is fully armed, ready to be released upon landing.

After firing, the pyrotechnic firing mechanism must be replaced before reusing the release machanism, but the removal of the used firing mechanism and its replacement is a simple process. Both forms of arming devices operate to maintain a safe or unarmed position of the release mechanism during deployment of the parachute when swaying of the load and parachute might otherwise cause premature release of the load from the parachute. After the lapse of a predetermined period of time, however, the lock bars are unlocked and dropped by force of gravity to a position out of engagement with the toggle ribs 42. If, due to some malfunction or rigging blunder, the forces on the load suspensions are badly out of balance, side forces exerted on the locking mechanism by the toggle and its ribs 42 would prevent the lock bars from falling, and thus prevent mid-air release of the load.

The drop or lock position of the release device is illustrated in FIGURES 2, 3, 4, 5, 6, 11 and 16, and in this position the toggle is locked in position by the lock arms 53 which are maintained in their upper position by the piston rod 69 and arming wire 74 in the hydraulic time device, or by the detent 81 in the pyrotechnic time device. As the parachute is deployed the cord 75 or 85 acts to start the operation of the time delay mechanism. In the hydraulic form, the wire 74 is withdrawn by cord 75 as the parachute opens, and the coil spring 62 starts moving the drive piston into its cylinder, thereby forcing fluid past screw valve 69 into cylinder 55. When the drive piston 59 moves inwardly to the position shown in FIG- URE 10, the end of drive piston rod 60 is withdrawn completely from opening 72, although still confined by the vertical groove 71, and at this time the lock bars 53 together with the base 51 drop by gravity to their lower inoperative position out of engagement with the toggle 40. The release device is then completely armed and ready to release the load. In the pyrotechnic time delay mechanism, the cord 85 starts the operation of the timer to finally operate the detent 81 so as to permit dropping of the lock bars 53 to their lower, inoperative position illustrated in FIGURE 18.

The operation of the disconnect is somewhat schematically illustrated in FIGURES 6, 7, 8, 9, 11 and 12. The locked position of the toggle is shown in FIGURES 6 and 11 in which the lock bars engage the toggle ribs 42 to maintain the locked position of the toggle. The armed position of the parts is illustrated in FIGURE 7 in which the parts are in the same position as in FIGURE 6 except for the time delay locking mechanism which has dropped to its inoperative position. In both the locked and armed positions shown in FIGURES 6, 7 and 11 the axis of the toggle pin 44 is in the same vertical plane as the axis of the plate openings 32 and the center of arculate slide grooves 34 and preferably coincides with such center. The spaced toggle ridges 41 are firmly seated in the spaced grooved sockets 39 in the lower surface of the bridge 31 to provide a broad base for a stable connection between the load and parachute slings during descent. The weight of the load is transmitted through the plates 25 and 26 and bridge 31 to the toggle 40, and from the toggle through the suspension link 48 to the parachute slings. The slide clamp 35 is disposed between the side arms of the suspension link 48 and maintained in position centrally of the arcuate grooves 34 by the side arms of the link 48. When the suspension link 48 is moved to either side of the center of the plates 25 and 26, the slide clamp 35 is moved in the same direction in the grooves 34 because it is confined between the side arms of the suspension link.

Because of the seating of the spaced toggle ridges 41 in the spaced bridge sockets 39 and the pivotal connection of the link 48 to the toggle 40 at the axis of the toggle pin, the resultant of the parachute forces must act through the toggle pin axis for equilibrium. Since the only other external forces acting on the release are the load suspension forces, the parachute force resultant must be the equilibrant of the load suspension forces. This equilibrant normally acts along the vertical arrow A in FIG- URE 7, and as long as this equilibrant acts between the arrows B and C in FIGURE 7, the toggle 40 will not rotate but will remain seated in both bridge sockets 39. Arrow B passes through the axis of toggle pin 44 and the axis of the right hand bridge socket 39 while arrow C passes through the toggle pin axis and the axis of the left hand socket 39. So long as the toggle remains seated in both bridge sockets 39, the space between the top of slide clamp 35 and the relieved portion of the upper arm of the suspension link 48, indicated by dimension D in FIGURES 8 and 9, remains so small as to prevent removal of the fingers 24 from the slide clamp.

As tensions in the slings 22 become unequal at landing when the parachutes blow to one side, the toggle remains seated in sockets 39 until the equilibrant acts outside of the arrows B-C, that is outside of a line passing through the axes of the toggle pin 44 and one of the sockets 39, at which time the toggle will fulcrum or pivot about the socket axis as indicated in FIGURES 9 and 12, and the toggle pin 44 moves to the end of the arcuate groove 45. As illustrated in FIGURE 8, the toggle 40 remains seated when the equilibrant acts through the axis of the pin 44 and the axis of one of the bridge sockets 39 as indicated by the arrow B, but as the equilibrant moves outside of this arrow B the toggle will move over its dead center toward the outside end of the groove 45 as it fulcrums or rotates about the axis of bridge groove 39. The initial pivotal movement of the toggle away from its central position of equilibrium forces the suspension link 48 and side plates 25 and 26 in vertical opposite directions until the toggle pin 44 passes its dead center, and this initial separating movement is normally prevented by the weight of the load acting in the direction of arrow A in FIGURE 7 even during swinging movements during descent. When the load lands, however, unequal tensions in slings 22 result, even if wind is still acting on the parachutes and the toggle is thereafter free to move laterally from its position of equilibrium. During the state of equilibrium the suspension link pivot center, which is the axis of the toggle pin 44, substantially coincides with the center of the arcuate groove 34 so that pivotal movement of the link 48 or movement of the slide 35 in groove 34 will not affect the dimension D between the slide 35 and link 48. However, lateral movement of toggle 40 away from its position of equilibrium acts to move the toggle pin 44 laterally away from the center of the arcuate groove 34 land from the center line of the side plates 25 and 26, thereby moving the suspension link 48 and its pivotal axis laterally and greatly increasing the dimension D as illustrated in FIGURE 9. Further pivotal movement of the suspension link from the position of FIGURE 9 will increase the dimension D to its fullest extent. The increase in dimension D is caused by the lateral separation or spacing of the pivot axis of link 48 and the axis of the slide groove 34, as well as by the relative lateral movement between the link 48 and the side plates 25 and 26.

As the dimension D increases due to lateral movement of the toggle and suspension link relative to the bridge 31 and slide 35, the sling fingers 24 will be freed from confinement between the slide clamp flanges 36 and will then be free to be cammed outwardly about their pivots due to the inclined lower surfaces of the underside of the upper arm of suspension link 48, resulting in complete release of the fingers 24 and the parachutes from the suspension link 48. The pull of the wind on the parachutes urges the fingers 24 to their release position as the dimension D increases and also causes pivotal movement of link 48 about its axis. Referring to FIGURES 2 and 3, it will be seen that the dimension D is normally of such small value that the fingers 24 extend down within the channel between the flanges 36 of the slide clamp, and that if the dimension D is increased to a value such that the clamp flanges 36 are moved below the ends of the fingers 24, the fingers will be free to move away from the suspension link 48 and disconnect the attached parachute from the load.

Any number of parachutes may be attached to the release device, depending on the size of the suspension link and the requirements of the load, and such par-achutes will be released instantly when the parts are tilted to the position shown in FIGURE 9. By arranging the release device with its long dimension normal to the long dimension of the load platform, the device will be very sensitive when the cargo platform lands with its long dimension normal to the direction of drift, which is the position in which upsetting of the load is most likely to occur. Contrary to the relaxation type of release which fails to operate in high winds due to the continued pull of the parachute, the present tilt type release functions best in high winds which blow the parachutes to one side, thereby tilting the release. The only situation in which the release might not ope-rate is one in which zero wind conditions exist, and under such conditions no harm is done because no upsetting or dragging of the cargo could result in the absence of wind.

The lock or arming mechanism positively prevents operation of the release during unstable deployment conditions, and the design of the release mechanism prevents operation of the release durin the more stable conditions after deployment even though considerable swaying takes place during descent, because the weight of the load will prevent rocking of the toggle to its release position until the cargo lands and the wind pull on the parachute acts to tilt the release. Where the hydraulic arming mechanism is used, the release can be used over and over again without replacement of any parts, and where the pyrotechnic arming device is used, only the pyrotechnic element need be replaced, and such replacement is extremely simple.

While the preferred embodiment of the invention has been shown and described, it is to be understood that various changes in the size, shape and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

I claim:

1. In a parachute disconnect for automatically releasing a parachute from its load when the load contacts the ground, a main body element and a suspension link element, means to connect one of said elements to the load and the other of said elements to the parachute, one of said connecting means being releasable, an abutment and toggle connection between the body element and suspension link element, the abutment being rigidly secured to one of said elements and the toggle having a pivotal connection adjacent its vertical center line to the other of said elements, the toggle normally having two spaced fulcrum areas of engagement with the abutment, the fulcrum areas being spaced substantially equidistantly from the vertical center line of the toggle to provide a normally stable connection between the body and link elements in which the weight of the load during descent will resist any pivotal movement of the toggle about either of its fulcrum areas, the releasable connective means comprising cooperating clamping surfaces carried by the body and suspension link elements, the clamping surfaces being closely arranged in clamping position when the toggle is in its normal descent position with both of its fulcrum areas in engagement with the abutment, and means responsive to tilting of the disconnect caused by inequality of load tensions at landing when the parachute blows to one side to move the toggle laterally about one of its fulcrum areas and separate the clamping surfaces to their release position.

2. The parachute disconnect of claim 1 in which an arming mechanism is movable from an operative position in which it engages the toggle in the normal position of the toggle to prevent movement of the toggle about either of its fulcrum areas, to an inoperative position out of contact with the toggle to permit movement of the toggle about either of its fulcrum areas.

3. The parachute disconnect of claim 1 in which one of the clamping surfaces of the releasable means comprises a slide clamp movable in an arcuate path the axis of which substantially coincides with the axis of the toggle center line pivotal connection in the normal position of the toggle, but which is spaced a substantial distance from the axis of the toggle pivotal connection in the laterally fulcrumed release position of the toggle.

4. In a parachute disconnect for automatically releasing a parachute from its load when the load contacts the ground, a main body element adapted to be connected to the load, a suspension link adapted to be releasably connected to a parachute, a rigid abutment carried by the body member, a toggle having a pivotal connection adjacent its vertical center line to the suspension link, the toggle having two spaced fulcrum areas normally in engagement with the rigid abutment, the fulcrum areas being spaced substantially equidistantly from the vertical center line of the toggle to provide a normally stable connection between the body element and suspension link in which the weight of the load during descent will resist any pivotal movement of the toggle about either of its fulcrum areas, the releasable connection to the parachute comprising a slide clamp carried by the body element adjacent the upper portion of the body element and movable relative to the body in an arcuate path the axis of which substantially coincides with the axis of the pivotal connection between the suspension link and toggle in the normal descent position of the toggle but which is spaced a substantial distance from the axis of such pivotal connection in the laterally fulcrumed release position of the toggle, the slide clamp being arranged in close clamping relation to a clamping portion of the suspension link in the normal descent position of the toggle in which both toggle fulcrum areas are in engagement with the abutment, and means responsive to the tilting of the disconnect caused by inequality of load tensions at landing when the parachute blows to one side to move the toggle laterally about one of its fulcrum areas and thereby separate the slide clamp from the clamping portion of the suspension link to release the parachute from the disconnect.

5. The parachute disconnected of claim 4 in which an arming mechanism is movable from an operative position in which it engages the toggle in the normal position of the toggle to prevent movement of the toggle about either of its fulcrum areas, to an inoperative position out of contact with the toggle to permit movement of the toggle about either of its fulcrum areas.

6. The parachute disconnect of claim 4 in which the main body element comprises a pair of spaced plates separated near their upper portions by the rigid abutment, the toggle being arranged between the plates, and toggle guide means carried by the plates and engaging the toggle to maintain the toggle in contact with the abutment while permitting limited pivotal movement of the toggle about either of its fulcrum areas.

7. The parachute disconnect of claim 6 in which the suspension link is connected to the toggle between the body plates and extends above the plates and the slide clamp, the side plates having arcuate grooves on their inner surfaces to silda bly receive projections on the slide clamp and provide a closed trackway to guide and limit the sliding movement of the slide clamp about the axis of the arcuate grooves.

8. The parachute disconnect of claim 6 in which an arming safety mechanism is carried between the body plates, the arming mechanism including a lock bar, interfitting elements on the lock bar and toggle, a detent carried by the arming mechanism and movable from a locking position in which the lock bar is held in engagement with the toggle to an armed position in which the lock bar is free to move to an unlocked position out of contact with the toggle, a time delay device associated with the detent to move the detent from its locking position to its armed position after the lapse of a predetermined length of time, and an arming cable associated with the time delay device and movable to start the operation of the time delay device.

9. The parachute disconnect of claim 8 in which the time delay device includes a hydraulic piston connected to the detent, and resilient means normally urging the piston in a direction to move the detent from its locked position to its armed position.

10. The parachute disconnect of claim 9 in which the time delay device includes an adjustable valve to regulate the rate of movement of the hydraulic piston in response to the urging of the resilient means.

11. The parachute disconnect of claim 9 in which the body plates are provided with means to retain the arming 12 mechanism between the plates in the armed position of the parts.

12. The parachute disconnect of claim 8 in which the time delay device includes a pyrotechnic element operable to move the detent from its locked to its armed position.

13. In a parachute disconnect for automatically releasing a parachute from its load when the load contacts the ground, a main body, a slide clamp carried by the main body and movable in an arcuate path with respect to said body, a suspension link pivotally associated with the main body and having a portion normally disposed in clamping relation to the slide clamp, the axis of the suspension link pivot normally being substantially coincident with the axis of the arcuate path of the slide clamp, means responsive to substantial tilting of the disconnect caused by inequality of the load tensions at landing when the parachute blows to one side to cause movement of the axis of the suspension link pivot laterally with respect to the axis of the arcuate path of the slide clamp to there- 'by bring about a separation of the slide clamp and the portion of the suspension link normally disposed in clamping relation to the slide clamp.

14. The parachute disconnect of claim 13 in which an arming mechanism is movable from an operative position in which it maintains the substantial coincidence of the axes of the suspension link and the arcuate path of the slide clamp to a position in which it permits free relative movement between such axes.

15. The parachute disconnect of claim 14 in which the arming mechanism includes a time delay device.

References Cited UNITED STATES PATENTS 2,414,023 1/1947 Cooper 294-83 2,889,168 6/1959 Engelhardt 294-83 3,081,122 3/1963 Jungersen 29483 EVON C. BLUNK, Primary Examiner.

H. C. HORNSBY, Assistant Examiner. 

1. IN A PARACHUTE DISCONNECT FOR AUTOMATICALLY RELEASING A PARACHUTE FROM ITS LOAD WHEN THE LOAD CONTACTS THE GROUND, A MAIN BODY ELEMENT AND A SUSPENSION LINK ELEMENT MEANS TO CONNECT ONE OF SAID ELEMENTS TO THE LOAD AND THE OTHER OF SAID ELEMENTS TO THE PARACHUTE, ONE OF SAID CONNECTING MEANS BEING RELEASABLE, AN ABUTMENT AND TOGGLE CONNECTION BETWEEN THE BODY ELEMENT AND SUSPENSION LINK ELEMENT, THE ABUTMENT BEING RIGIDLY SECURED TO ONE OF SAID ELEMENTS AND THE TOGGLE HAVING A PIVOTAL CONNECTION ADJACENT ITS VERTICAL CENTER LINE TO THE OTHER OF SAID ELEMENTS, THE TOGGLE NORMALLY HAVING TWO SPACED FULCRUM AREAS OF ENGAGEMENT WITH THE ABUTMENT, THE FULCRUM AREAS BEING SPACED SUBSTANTIALLY EQUIDISTANTLY FROM THE VERTICAL CENTER LINE OF THE TOGGLE TO PROVIDE A NORMALLY STABLE CONNECTION BETWEEN THE BODY AND LINK ELEMENTS IN WHICH THE WEIGHT OF THE LOAD DURING DESCENT WILL RESIST ANY PIVOTAL MOVEMENT OF THE TOGGLE ABOUT EITHER OF ITS FULCRUM AREAS, THE RELEASABLE CONNECTIVE MEANS COMPRISING COOPERATING CLAMPING SURFACES CARRIED BY THE BODY AND SUSPENSION LINK ELEMENTS, THE CLAMPING SURFACES BEING CLOSELY ARRANGED IN CLAMPING POSITION WHEN THE TOGGLE IS IN ITS NORMAL DESCENT POSITION WITH BOTH OF ITS FULCRUM AREAS IN ENGAGEMENT WITH THE ABUTMENT, AND MEANS RESPONSIVE TO TILTING OF THE DISCONNECT CAUSED BY INEQUALITY OF LOAD TENSIONS AT LANDING WHEN THE PARACHUTE BLOWS TO ONE SIDE TO MOVE THE TOGGLE LATERALLY ABOUT ONE OF ITS FULCRUM AREAS AND SEPARATE THE CLAMPING SURFACES TO THEIR RELEASE POSITION. 